SMT Component Failure
Some SMD components are very small, making it inconvenient to use ordinary multimeter test leads for testing and repair. This can easily lead to a short circuit or make it difficult to touch the metal part of the component pin on a circuit board coated with an insulating coating. I have a simple solution to share that will greatly simplify the detection process.
Take two sewing needles of the smallest size and attach them to the multimeter test leads. Next, grab a thin copper wire from a multi-strand cable and use it to bind the test leads and sewing needles together. Make sure to solder them together securely. By following this method, you can measure SMT components with the small needle tips without the risk of causing a short circuit. The needle tips can easily penetrate the insulating coating and reach the key parts without the need to remove the coating. This technique will save you time and effort during testing and repair work.
Short-circuit Failure of Public Power Supply
In circuit board maintenance, encountering a short-circuit of the public power supply is a serious fault. This is because multiple devices share the same power supply, and any device using this power supply may be suspected of short-circuiting.
For boards with few components, the method of “hoeing the earth” can eventually locate the short-circuit point. However, if there are too many components, success with this method may depend on luck. A more efficient method is recommended here, as it can yield quicker results with less effort.
It is essential to use a power supply with adjustable voltage and current, with a voltage range of 0-30V and current range of 0-3A. Such power supplies are relatively inexpensive, costing around 300 yuan. Adjust the open circuit voltage to match the device power supply voltage. Begin by setting the current to the minimum, then apply this voltage to the power supply points of the circuit, such as the 5V and 0V terminals of the 74 series chip. Gradually increase the current based on the level of the short circuit.
While testing, touch the devices with your hand. If you detect a significantly heated device, this is likely a damaged component that should be removed for further testing and confirmation. Be mindful that the voltage applied should not surpass the device’s working voltage, and ensure the correct polarity to prevent damage to other functioning devices.
Some SMD components are very small, making it inconvenient to use ordinary multimeter test leads for testing and repair. This can easily lead to a short circuit or make it difficult to touch the metal part of the component pin on a circuit board coated with an insulating coating. I have a simple solution to share that will greatly simplify the detection process.
Take two sewing needles of the smallest size and attach them to the multimeter test leads. Next, grab a thin copper wire from a multi-strand cable and use it to bind the test leads and sewing needles together. Make sure to solder them together securely. By following this method, you can measure SMT components with the small needle tips without the risk of causing a short circuit. The needle tips can easily penetrate the insulating coating and reach the key parts without the need to remove the coating. This technique will save you time and effort during testing and repair work.
Short-circuit Failure of Public Power Supply
In circuit board maintenance, encountering a short-circuit of the public power supply is a serious fault. This is because multiple devices share the same power supply, and any device using this power supply may be suspected of short-circuiting.
For boards with few components, the method of “hoeing the earth” can eventually locate the short-circuit point. However, if there are too many components, success with this method may depend on luck. A more efficient method is recommended here, as it can yield quicker results with less effort.
It is essential to use a power supply with adjustable voltage and current, with a voltage range of 0-30V and current range of 0-3A. Such power supplies are relatively inexpensive, costing around 300 yuan. Adjust the open circuit voltage to match the device power supply voltage. Begin by setting the current to the minimum, then apply this voltage to the power supply points of the circuit, such as the 5V and 0V terminals of the 74 series chip. Gradually increase the current based on the level of the short circuit.
While testing, touch the devices with your hand. If you detect a significantly heated device, this is likely a damaged component that should be removed for further testing and confirmation. Be mindful that the voltage applied should not surpass the device’s working voltage, and ensure the correct polarity to prevent damage to other functioning devices.
